The present invention relates to a shear force gauge for use with elongate catheter and wire elements to monitor the amount of tension applied thereto and, in the preferred embodiment, limit that tension. It is particularly concerned with such a gauge which may be used in an improved embolectomy apparatus and method to limit the amount of shear force exerted on the wall of an artery during the embolectomy process.
The prior art teaches controlling the inflation of expansible tip balloon catheters (see, for example, Foderick U.S. Pat. No. 3,211,150). It is also known to use balloon catheters for embolectomy purposes. See Fogarty U.S. Pat. No. 3,435,826 and Fettel Pat. No. 3,978,863. The latter patent is particularly interesting in that it discloses an apparatus and method for monitoring and controlling the inflation of an embolectomy balloon. External indicators to show the inflation of an internal balloon in a urinary catheter are also known (see, for example, McWhorter U.S. Pat. No. 3,543,759).
While the above prior art teaches embolectomy catheters and methods and apparatuses for controlling the inflation of a catheter balloon, it does not teach the concept of measuring the tension of the catheter on an embolectomy balloon to monitor and limit the shear force applied to an artery during embolectomy catheter use.